1. The operation layer is a detailed, application-oriented, frequently accessed current value, which is accurate at the moment of access. When operational data is imported into the data warehouse, attention should be paid to consistent transformation. For example, different nodes have different encoding formats, and they need to be converted into a unified format when they are finally stored in the data warehouse.
2. Data warehouse layer: It stores the integrated historical data that cannot be updated, and also stores some exported data.
3. Department layer: On the basis of the data warehouse, it is established to meet the special needs of the department according to the needs of end users.
4. Individual layer: Most of the heuristic analysis is done in the individual layer. Heuristic analysis means that problem solving is a method of discovery based on empirical rules.